docs: def redis(self):
          """
          A :class:`redis.StrictRedis` instance, configured to connect to the
          current application's Redis server.
          """
          redis_url = current_app.config.get("SSE_REDIS_URL")
          if not redis_url:
              redis_url = current_app.config.get("REDIS_URL")
          if not redis_url:
              raise KeyError("Must set a redis connection URL in app config.")
          return StrictRedis.from_url(redis_url)